Mixed oxide containing a lithium manganese spinel and process for its preparation

Abstract

A mixed oxide containing a) a mixed-substituted lithium manganese spinel in which some of the manganese lattice sites are occupied by lithium ions and b) a boron-oxygen compound. Furthermore, a process for its preparation and the use of the mixed oxide as electrode material for lithium ion batteries.

What is claimed: 
     
       1. A process for the preparation of a mixed oxide containing a mixed-doped hyperstoichiometric lithium manganese spinel comprising:
 (a) providing components comprising a lithium component, a manganese component, and a boron component, and optionally a component comprising N, wherein N is selected from the group consisting of Al, Mg, Co, Ni, Cu and Cr and optionally a component comprising M, wherein M is selected from the group consisting of Zn, Mg and Cu, wherein at least some of the components are in a dry, powdery form; 
 (b) preparing a solid mixture by mixing at least some of the dry, powdery components of (a) to form a mixture in dry, powdery form; 
 (c) preparing a liquid mixture comprising a solvent and a portion of the components of (a) dissolved and/or suspended in the solvent, 
 (d) mixing the solid mixture of (b) and the liquid mixture of (c) with each other; 
 (e) drawing the solvent off the mixture obtained in step (d); 
 (f) calcining the mixture obtained in (e) at a temperature of more than 300° C.;
 wherein the stoichiometric quantities of the components of the first and second portions are selected in such a way that a mixed oxide of the following formula results:
   [(Li 1−a M a )(Mn 2−c−d Li c N d )O x ]. b (B z O y H u X v ) 
 
 
 wherein: 
 0≦a<0.1; 
 d<1.2 
 3.5<x<4.5; 
 0.01<c<0.06
 z=1, 2 or 4 
 y=1, 2, 3 or 7 
 u=0, 1, 2 or 3 
 v=0, 1, 2 or 3 
 
 0.01<b<0.5; 
 M is at least one element from the group of Zn, Mg and Cu; 
 N is at least one element from the group of Al, Mg, Co, Ni, Cu and Cr; and 
 X is at least one element from the group Li, Na, K; 
 whereby a lithium manganese spinel is obtained having a d 50  primary crystallite size of at least 0.5 μm. 
 
     
     
       2. The process according to  claim 1 , wherein the calcining of (f) is carried out in at least two steps, wherein calcination is at temperatures of 300° C. to 600° C. in a first step and at temperatures of 600° C. to 900° C. in a second step. 
     
     
       3. The process according to  claim 1 , wherein the D 50  particle size value of the lithium component is less than 30 μm. 
     
     
       4. The process according to  claim 3 , wherein before the mixing according to (d) the manganese component has a D 95  particle size value measured by laser granulometry of less than 30 μm. 
     
     
       5. The process according to  claim 1 , wherein the solvent of the liquid mixture of (c) is water. 
     
     
       6. The process according to  claim 5 , wherein the liquid mixture of (c) contains a portion of the manganese component and/or the component comprising N. 
     
     
       7. The process according to  claim 6 , wherein the solid mixture of (b) is stirred into the liquid mixture of (c). 
     
     
       8. The process according to  claim 1 , wherein the components of (a) are provided in the form of their nitrates, acetates, oxides, hydroxides and/or carbonates. 
     
     
       9. The process according to  claim 4 , wherein the manganese component is selected from the group consisting of manganese carbonate, manganese oxide and manganese dioxide. 
     
     
       10. The process according to  claim 1 , wherein the values chosen for b and d are 0.0025<b<0.025 and 0.05<d<0.2. 
     
     
       11. The process according to  claim 10 , wherein the values chosen for b, d and a are 0.0025<b<0.025, and 0.08<d<0.15, and 0.005<a<0.02. 
     
     
       12. The process according to  claim 11 , wherein N is selected from Al and Mg, and M is Zn.